Each subsequent generation of mobile computing devices, such as notebooks and tablets, is smaller and thinner than the preceding one. Typical notebooks computers were fully 25 mm thick and contained the long-standard 9.5 mm tall 2.5″ hard disk drive (HDD). Newer notebooks are only 18 mm thick and use a 7 mm tall HDD. Some notebooks are thinner yet, and use solid-state memory, which can be less than 2 mm tall. Thin notebooks with HDDs conventionally route all other componentry around the relatively tall HDD, such that the bottom structure of the chassis, the palmrest structure and sway space for the HDD are the only features above and below the HDD.
A 7 mm 2.5″ HDD is conventionally integrated with a mating Serial Advanced Technology Attachment (SATA) connector and cable that runs to the laptop's motherboard. These add to the overall integrated length of the HDD. The chassis bottom and palmrest must be held together (typically with screw bosses) at the periphery of the HDD, but outside of the HDD's rectangular form factor. These structures also add to the integrated length and width of the HDD. Many notebooks feature chassis bottoms that curve up from a flat underside to the front edge and/or sides of the notebook. Many notebook chassis also radius the left and right front corners. With the rectangular block geometry of the 7 mm 2.5″ form factor, the HDD must be set-back from the notebook edges (front, side and bottom) and from the front corners to accommodate these curved features. These set-backs also increase the integrated length, width and height of the HDD.